[G14_run] HD target lengths for Silver and Gold

[Tsuneo Kageya]

Hi Alessandra,


I have some questions and suggestions.


Q1. At your analysis note of the chapter 4.1.6 at p. 44, you are writing the HD target lengths

of 4 cm (Gold) and 5 cm (Silver).  They may be right, but I wonder how do you define them ?


Q2. When you use both of data, Silver and Gold, to extract asymmetries, I wonder if we have to consider the amount

of HD material lost for Silver target.   I did not read the whole anaysis note yet and you may have already considered

this.


 I am attaching three PDF files.   I think I used the same cuts for (1) and (2), but don't remember which W-bins were

 used.


(1) Silver_Zvertex.pdf


(2) Gold_Zvertex.pdf


(3) G14_tgt_cell_dimensions.pdf


 For (1) z vertex distributions from MVRT for HD Silver target run (black), empty_b target run (blue)

and subtracted (red) corresponding to the pure HD.  Smaller entries between z = -11 and -8 cm than z = -8 cm

and -5 cm are coming from the fact that HD material was evapolated and lost during one of the target transfers.


 For (2) z vertex distributions from MVRT for HD Gold target run (black), empty_a target run (blue)

and subtracted (red) corresponding to the pure HD..


 We condensed the similar amounts of HD materials to the call 21a and 19b, but for 21a we lost some.


 (3) shows the dimensions of the three target cells used for g14.   21a and 19b were used for Silver and Gold

runs, respectively.   According to the report, there are differences of location of the HD target materials

 (Silver and Gold) due to the different dimensions of the target cells (21a and 19b).

The data for empty-a and -b were taken with the cell, 21a; the locatios of entrance and exit windows for Silver

and Empty-b are the same, while those for Gold and Empty-a are slightly different.

>From (1) and (2), it is hard to see clear differnces of the window position, because the differences are mm

and may be too small to see on them.

You may consder these things for the empty subtractin of Gold target and vertex cut.



 I think for Gold target, the flat region of the distribution is between z = -10 and -6 or -5.5 cm and we may define

the length of 4 or 4.5 cm.

We condensed the HD material to the call to have 5 cm of length included the shrinkage of HD

material when frozen. For Silver target, it may be hard to define the length, because the evaporated HD may have

frozen in the upstream region like z = -10 cm.


 My opinion is to use 4.5 cm for the both target lengths and to describe the HD material conditions in the analysis note.


   Regards, Tsuneo Kageya.





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